Band-center metal-insulator transition in bond-disordered graphene
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arXiv
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| Format: | Preprint |
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2023
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| author | Nayak, Naba P. Sarkar, Surajit Damle, Kedar Bera, Soumya |
| author_facet | Nayak, Naba P. Sarkar, Surajit Damle, Kedar Bera, Soumya |
| contents | We study the transport properties of a tight-binding model of non-interacting fermions with random hopping on the honeycomb lattice. At the particle-hole symmetric chemical potential, the absence of diagonal disorder (random onsite potentials) places the system in the well-studied chiral orthogonal universality class of disordered fermion problems, which are known to exhibit both a critical metallic phase and a dimerization-induced localized phase. Here, our focus is the behavior of the two-terminal conductance and the Lyapunov spectrum in quasi-1D geometry near the dimerization-driven transition from the metallic to the localized phase. For a staggered dimerization pattern on the square and honeycomb lattices, we find that the renormalized localization length $ξ/M$ ($M$ denotes the width of the sample) and the typical conductance display scaling behavior controlled by a crossover length-scale that diverges with exponent $ν\approx 1.05(5)$ as the critical point is approached. However, for the plaquette dimerization pattern, we observe a relatively large exponent $ν\approx 1.55(5)$ revealing an apparent non-universality of the delocalization-localization transition in the BDI symmetry class. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2304_09674 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Band-center metal-insulator transition in bond-disordered graphene Nayak, Naba P. Sarkar, Surajit Damle, Kedar Bera, Soumya Disordered Systems and Neural Networks Mesoscale and Nanoscale Physics We study the transport properties of a tight-binding model of non-interacting fermions with random hopping on the honeycomb lattice. At the particle-hole symmetric chemical potential, the absence of diagonal disorder (random onsite potentials) places the system in the well-studied chiral orthogonal universality class of disordered fermion problems, which are known to exhibit both a critical metallic phase and a dimerization-induced localized phase. Here, our focus is the behavior of the two-terminal conductance and the Lyapunov spectrum in quasi-1D geometry near the dimerization-driven transition from the metallic to the localized phase. For a staggered dimerization pattern on the square and honeycomb lattices, we find that the renormalized localization length $ξ/M$ ($M$ denotes the width of the sample) and the typical conductance display scaling behavior controlled by a crossover length-scale that diverges with exponent $ν\approx 1.05(5)$ as the critical point is approached. However, for the plaquette dimerization pattern, we observe a relatively large exponent $ν\approx 1.55(5)$ revealing an apparent non-universality of the delocalization-localization transition in the BDI symmetry class. |
| title | Band-center metal-insulator transition in bond-disordered graphene |
| topic | Disordered Systems and Neural Networks Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2304.09674 |